As someone who has worked in the mobile pc support industry, what HN users would call "common sense" isn't really that common. I don't think developers and power users truly understand how common the huge gap is between them and non-technical users. I've given sessions on things as simple as mouse movement and basic GUI file management with drag and drop is a challenge.

Don't get me wrong, I absolutely do not support "walled gardens" that are now becoming common and I don't think they are the solution to this problem. Power should always be left in the hands of the user, the solution is education. This is of course a social issue and one of gigantic scale. There are so many strong political hurdles to overcome that I'm not surprised that the industry has taken the approach it currently has.